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The Venus Transit 2004
Walkiry writes "In just 47 days our friendly neighbour planet Venus will be passing right in between Earth and good ol' Sun, giving us the chance to see a small black spot going accross the disk (last one was in 1882). This is called the Venus Transit. The interesting thing is that there is a project asking for volunteers to perform their own measurements of the phenomena and submit their own results, in what will be the first accurate and public measurement of an extraterrestrial distance. Do you have a spare telescope and some free time on June 8th?"
Apaprently, the next Venus transit after this one will be in 2012, but the next two after that won't be until 2117 and 2125. Looks like a once in a lifetime deal. (source: http://sunearth.gsfc.nasa.gov/eclipse/transit/venu s0412.html)
It was in a situation like that that Venus athmosphere (its clounds) was discovered, when Venus was against the sun an astromer saw a fog over the planet. A lot of light passed trough where previously was thoug to be solid.
This is what i found in Wikipedia on Venus Transits:
"Transits of Venus, when the planet crosses directly between the Earth and the Sun' visible disc, are important astronomical events. The first such transit was observed on December 4, 1639 by Jeremiah Horrocks and William Crabtree. A transit in 1761 observed by Mikhail Lomonosov provided the first evidence that Venus had an atmosphere, and the 19th century observations of parallax during its transits allowed the distance between the Earth and Sun to be accurately calculated for the first time. The previous set of transits of Venus occurred within the interval of 1874 - 1882, and the next set of transits will occur in the period of 2004 - 2012."
"Anyone who quotes me in their
can't see it from north america!
Most astronomical events seem to not be visible from or get clouded out in my area.
no big sig
What's proabaly better is a projection scope. A prpoer one is very expensive, but you can just hold any convex lense or piece of shirt cardboard with a really tiny hole in it above a piece of white paper. You'll need very good resolution to see this though, so you should probably calculate that ahead of time.
Sig:Why copyright isn't a fundamental human right
If you have a smaller telescope, or a a pair of binolculars, you can project an image of the sun onto a sheet of paper through the eyepiece. Use a cardboard box to make a darker area for the paper to be in. If there is some distance to the paper, the image of the Sun will be big enough that it will not burn the paper. Experiment with distance and focus to see what works.
Or you can just buy a Solar Viewer. American Science & Surplus has 'em for under $100.
I have a spare telescope and the free time, but I live in California.
The west coast of North America and most of South America won't be able to see the transit.
a,e,i,o,u and sometimes w and y (at be if of up cwm by)
you should go here
I have no developed opinion on the bararity of foo. -homeobocks, Gentoo Forums
Benmore Peak Observatory (http://www.observatory.org.nz) in New Zealand's South Island will be hosting a bunch of visitors for this one. Not only is the view of Venus going to be good, so is the view of the lakes and snow-clad mountain peaks around it. I was there in 2000 and it's just absolutely outstanding (and they always have lots of icy cold beer)! Thoroughly recommended.
Despite warnings every year people get blinded because they wanted to see a partial eclipse or some other solar event directly.
Use a telescope or binoculars and project the image onto a piece of white cardboard or paper.
Even just a few seconds can ruin your eyesight so be careful. It's no joke.
From 1882? I don't think so.
Think again. We do have photos of it. A movie has even been made.
- "Hear that?! The percolations are imminent! Cease your ingress!"
The other kind of sun filter fits over your eyepiece or inside your eyepiece. I once had a 2.4 inch refracting telescope that came with this piece of welder's glass that fit over the eyepiece. I never used it because I was warned not to.
The advantage of the objective sun filter (the ones I have seen advertised are aluminized mylar) is that 1) it blocks out intense sunlight before it even gets to your telescope, and 2) it is exposed to no more than normal sun intensity because it hasn't been concentrated by the telescope.
The wee bit of welder's glass at the telescope eyepiece is unsafe because it is getting the full focus of sunlight from the telescope and the thing and crack from the heat and then your eyeball is in peril.
The other safe method is projection through the telescope on to a piece of paper. Safe for one's eyes -- I ruined my beginner's refractor doing that because the heat cooked a cheap plastic element in the one eyepiece it came with.
Venus is the Roman equivalent to the Greek Aphrodite.
...accurate and public measurement of an extraterrestrial distance.
... determine these orbits far more accurately (by one or two orders of magnitude) than do the optical data." The report for the current latest general ephemeris on public release DE405, here, says much the same.
I doubt that the public project related to the 2004 transit is intended to obtain more accurate measurements than already exist, for the distances and timings associated with Venus.
For all of the inner planets, even the best professional optical telescope measurements are already so much less accurate than modern non-optical measurements, such as radar-ranging and spacecraft measurements, that optical data (except for the outer planets) did not contribute at all to the final data-sets that went to make up the current best professional ephemerides. This JPL report, about the latest-but-one of the professional solar-system ephemerides, DE403, says that "all of the optical observations for the Sun, Mercury, Venus and Mars were omitted from the least-squares adjustments leading to DE403. Newer and more accurate data-types
The project for measuring the timing of the June Venus transit looks like mainly an exercise in public awareness and education. Maybe there is also an aim of historical reconstruction, for doing something like re-assessing the performance of the old astronomers who measured previous transits, in an age when optical telescopes still did provide the only serious measurements available.
-wb-
The GONG is used to watch the Sun oscillate, or "ring," which provides mighty useful data on the solar interior. Helioseismology, in other words. See http://gong.nso.edu for details.
Credit Line: The GONG is operated by the National Solar Observatory which is operated by the Association of Universities for Research in Astronomy under a cooperative agreement with the National Science Foundation, for the benefit of the astronomical community.